This invention relates generally to apparatus for draining fluids from body cavities and for introducing fluids into body cavities. More particularly, this invention relates to an improved apparatus for positively locating a body cavity having fluctuating fluid pressure and then either draining fluids from the cavity or introducing fluids into it.
An apparatus for draining fluids from body cavities, including particularly the pleural cavity, is described in U.S. Pat. No. 4,664,660. The apparatus described in that patent includes a vented housing having a fluid-receiving chamber, an anti-reflux valve mounted within the housing and a catheter, extending from the housing, in communication with the chamber through the anti-reflux valve.
The apparatus of U.S. Pat. No. 4,664,660 is used in the drainage of fluids from the pleural cavity by inserting a solid trocar into the catheter so that the sharp tip of the trocar extends beyond the distal end of the catheter. A skin incision is then prepared and the trocar/catheter assembly is introduced into the pleural space through the incision. When the trocar is removed from the catheter, fluid drains from the pleural cavity through the catheter and the vented housing.
While the above-described apparatus represents a very important contribution to the art, in using it one cannot ascertain whether the open distal end of the trocar/catheter assembly is properly located in the pleural cavity until the trocar is removed. Since drainage cannot begin until the trocar is removed, the proper positioning of the catheter in the pleural space cannot be determined with the trocar in place. In addition, damage to the lung, heart and surrounding tissue could occur if the trocar is not removed as soon as the tip of the trocar catheter assembly enters the pleural space.
Another apparatus for draining fluids from body cavities, particularly aspiration of liquids from the pleural cavity, is disclosed in U.S. Pat. No. 4,447,235. The apparatus described in this patent includes a catheter/hollow needle assembly which is inserted into the pleural cavity. During the insertion procedure, a vacuum is maintained in the needle with a syringe so that liquid will enter the syringe for observation by the surgeon when the needle enters the pleural space. This device cannot function unless a vacuum is maintained. Also, it cannot signal subsequent dislocation of the catheter from the pleural space or completion of drainage since the syringe is disconnected (and cannot be reintroduced) after the initial insertion of the catheter in the pleural cavity.
A medical suction device with an indicator flag to signal the pressure being developed by the device is described in U.S. Pat. No. 4,404,924. The indicator flag is designed to stand upright when the pressure in the device is relatively high and to collapse when suction is developed. The flag, unfortunately, indicates the state of fill of the suction device, not the satisfactory location of a catheter in the body cavity being aspirated or the completion of the aspiration procedure. In addition, it has no application in a procedure conducted without vacuum assistance.
Finally, U.S. Pat. No. 4,164,938 describes a device for diagnosing the presence of a tension pneumothorax. This device includes a sleeve with a needle at one end for puncturing the chest wall and extending into the pleural cavity and a diaphragm at the other end which expands when the pressure in the pleural cavity is greater than atmospheric. Since this device does not vent fluid from the pleural cavity, the diaphragm does not provide any indication that venting is proceeding or that the pneumothorax has been resolved.